Daylighting (tunnels)

Daylighting a tunnel is to remove its "roof" or overlying rock and soil, thus exposing the railway or roadway to daylight. This could also be seen as converting the tunnel to a railway or roadway cut. Tunnels are often daylighted to improve vertical or horizontal clearances, for example to accommodate double-stack container trains or electrifying rail lines, where increasing the size of the tunnel bore would be impractical.

List of Daylighted Tunnels

• United States of America
  • Auburn Tunnel on the Schuylkill Canal, daylighted in 1857
  • Tunnel No. 5 on the Alaska Railroad's Seward-Anchorage line^[1]
  • Tunnel No. 5 on the Virginia & Truckee Railroad at Nevada S.R. 341 near Virginia City
  • The Gwynedd Cut on the North Pennsylvania Railroad, near North Wales, Pennsylvania, built as a tunnel between 1853 and 1856, daylighted in 1930 when the Reading Railroad electrified the line

References

1. ^ F. C. Weeks et al., "Tunnel 'Daylighting' on the Alaska Railroad," Transportation Research Record No. 1119, Geotechnology (1987).

See also

• Cut (earthmoving)
• Cutting (transportation)
• Daylighting (streams)